Overvoltage protection device of chopper, chopper and electric locomotive

Abstract

The invention provides an overvoltage protection device of a chopper, the chopper and an electric locomotive. The overvoltage protection device comprises a voltage detection unit, a first voltage comparison unit, a first time acquisition unit, an electric energy absorption unit and a fuse, wherein the voltage detection unit is arranged in an output end circuit of a voltage-decreasing chopper, the first voltage comparison unit is connected with the voltage detecting unit, the first time acquisition unit is connected with the first voltage comparison unit, the electric energy absorption unit is arranged behind an output end voltage detection unit of the voltage-decreasing chopper and is connected with the first time acquisition unit, and the fuse is connected in series with an input end circuit of the chopper. With the overvoltage protection device adopted, the output overvoltage of the chopper can be prevented from damaging components connected in later-stage circuits of the chopper, and therefore, the switching frequency of the chopper can be reduced under the premise that corresponding equipment is protected, and thus, the service life of the chopper can be prolonged, and the operational stability of a system using the chopper can be improved.

Description

technical field [0001] The invention relates to electrical control technology, in particular to an overvoltage protection device for a chopper, a chopper and an electric locomotive. Background technique [0002] With the increasing maturity of power electronic circuits and AC speed regulation technology, AC drive systems are more and more widely used in the field of electric locomotives. The AC drive systems of electric locomotives can be divided into traction drive systems and auxiliary converter systems. The existing auxiliary There are many design structures in the converter system, among which, the intermediate circuit power-taking mode is a widely used mode. [0003] The auxiliary converter system of this mode is usually equipped with a step-down chopper. First, the high-voltage direct current output by the intermediate circuit of the traction electric transmission system is stepped down through the step-down chopper and then output a voltage with a lower voltage level....

AI Technical Summary

Problems solved by technology

[0007] If the grid voltage fluctuates for a short time and the overvoltage energy is small, such as a few nanoseconds, it is not necessary to stop the step-down chopper at this time because the time is very short and the overvoltage energy is small; however, the existing overvoltage Under the voltage suppression protection method, once the grid voltage fluctuates instantaneously, the step-down chopper is controlled to stop working. This will cause frequent switching of the step-down chopper, which is not conducive to the stable operation of the auxiliary converter system, and has a negative impact on the system. The service life of electrical components is affected

Images